Twin tank woes

[autoxbird]

'91 F250 460, LB, twin tanks. The front tank works fine, the rear tank runs fine, but fills the front tank. I'm running out of parts to replace. So far, I've replaced the front pump, rear pump, and the updated external check valve on the front tank. Best as I could guess, the only parts left to replace are the rear check valve and the dash switch. What else could I be missing?

[GuitarJesus]

Auto,

from what I understand it's not the pump itself you have to replace, but the delivery module itself that controls the check and shuttle valves. I am doing the same thing myself, just bought a rear complete module (pump, delivery module, and sending unit). Also just bought the rear unit.

So if you simply replaced the pump itself, you need to replace what aftermarket companies will consider the sending unit. From what I've gathered (and somebody please correct me if I'm wrong), Ford considers the sending unit just the float and electrical connection for it. But aftermarket companies consider the inlet tubes (top piece of module) and the float to be the sending unit.

I could be wrong, but I think that's where you might need to look. By the way, the external check valve, where did you get the part to "update it"? I'd like to get that part so I don't have to worry about the delivery modules going haywire on me later.

Jeff